(AP) -- The mystery of what killed tens of thousands of fish that washed up along the Arkansas River late last year can't be solved, state wildlife officials announced Wednesday, but they do have a theory about what caused ...

With the number of salmon in the North Pacific having doubled in the past 50 years, scientists are increasingly concerned there may not be enough food to support them, and changing ocean conditions could make it even worse.

We hear so much about missing wild salmon and recently a record run. But Simon Fraser University scientists say a population explosion of hatchery and wild salmon in the North Pacific Ocean is leading hatchery fish to beat ...

Steelhead trout that are originally bred in hatcheries are so genetically impaired that, even if they survive and reproduce in the wild, their offspring will also be significantly less successful at reproducing, according ...